Effects Of Soil Mulching And Irrigation On Yield And Water Use Efficiency Of Several Crops

Global warming has intensified climate change,and result in higher global mean temperature and uneven distribution of precipitation.Moreover,the increasing scarcity of available water resources for agriculture,therefore increase crop water use efficiency(WUE)and crop yield have become the primary issues in agricultural production.Soil mulching can reduce the soil evaporation,improve soil moisture content and increase crop yield;Irrigation is also a practice to increase crop yield,but how to use irrigation water more effective remains to be further study.In this study,we collected 1483 observations from 122 published papers and used meta-analysis to investigate the effect of different soil mulching,different soil irrigation and different levels of drip irrigation on crop yield and water use efficiency.The aim is to(1)quantify the effects of different soil mulching on maize yield,water use efficiency and evapotranspiration;(2)quantify the effects of different soil irrigation on crop(cotton,maize,sorghum,pepper,tomato,cabbage,okra,and cucumber)yield and irrigation water use efficiency(IWUE);(3)quantify the effects of different levels of drip irrigation on crop(cotton,cabbage,and muskmelon)yield and irrigation water use efficiency in order to select the most optimal drip irrigation level for different crop;(4)evaluate the yield effects of different soil mulching,different soil irrigation,and different levels of drip irrigation in different soil types;and(5)estimate the effects to plastic mulching by precipitation and temperature,i.e.,under which precipitation and temperature conditions do the positive effects of plastic mulching on maize disappear.The results show that:1)Compared with no mulch + flat(CK),both straw mulch and plastic mulch were significantly increased maize yields and WUE(except for SMR),and that plastic mulch was more effective than straw mulch in increasing yields,particularly in cold and dry environments.PMR has the highest yields and is more effective in clay loam than in silt loam soils.Straw mulch,but particularly plastic mulch,increased the soil moisture compared to the CK treatment,while plastic mulch increased soil temperature,mainly in early stages of maize growth.2)Traditional irrigation(flood irrigation,furrow irrigation,and sprinkler irrigation)can effectively increase crop yield,but due to the large amount of water use,the irrigation water use efficiency was lower.Drip irrigation can not only significantly increased crop yield,but also effectively improved crop irrigation water use efficiency,and the yield effects of drip irrigation and plastic mulch was the highest.There was no significant difference in crop yield effects of drip irrigation(no mulch)under different soil types.3)Compare with 100% drip irrigation(1.0I),the deficit irrigation can not only effectively save irrigation water,but also further improve the crop irrigation water use efficiency,and it will not cause serious impact on crop yield,thus achieving higher economic benefits on the basis of reducing the cost of agricultural production.The optimal drip irrigation levels of cotton,muskmelon and cabbage were 0.8I,0.75 I and 0.6I(I,the water consumption under 100% full drip irrigation),respectively.There was also no significant difference in crop yield effects of different deficit irrigation(no mulch)under different soil types.4)The positive effects of plastic mulch on maize yield diminished with increasing mean growing-season temperature and precipitation,reaching zero when the growing-season precipitation was greater than 770 mm and the mean growing-season air temperature exceeded 24°C.But the straw mulch has not significant change across the precipitation and temperature gradients,including when the benefits of plastic mulch reached zero,thus it can be used as a mulch practice in better hydrothermal conditions.The result of this study can provide a scientific basis for agriculture to response to global changes.